One of the cardinal rules of documentation is always have a legend. See e.g. Documenting Software Architectures. It would be nice to have the option to create a legend. Bonus points if StarUML can automatically generate the legend based on UML elements in the diagram.

Please add support for C code!!

We can change the diagram background color, but not the editor background color. This is by far my biggest complaint with the tool and the one thing holding my team back from adopting it.

To be clear, I'm referring to the area of the tool with the grid background. The one that displays all of your diagrams.

I'd really like to see an option to lock a specific UML element to the workspace, so that if someone is making a namespace and has a lot of sub name spaces to move around they can avoid clicking on the containing one. I'm not sure how often people run into this when working with it, but I've found it somewhat vexing.

We should be able to, for example, double-click on "Attribute1" to select it, then right-click to paste from keyboard. It is possible to paste using Ctrl-V, but doing that many times gets annoying.

Add F2 for 'in-place' rename at least in Model Explorer.

Use case:
- Bob wants to rename element MyFirstClass in the model explorer
- Bob browse for MyFirstClass element in the Model Explorer
- Bob press F2 when on the MyFirstClass and in-place renames that element to MySecondClass

Is there a downloadable user's manual for StarUML?

how to convert a sequence diagram into a communication diagram (collaboration diagram)?

como pasar a español?

several bugs appear on new update

Adding a new column-item one by one can be very annoying.
How about adding column-items like this:

attr_name_1 : attr_type : length | attr_name_2 : attr_type : length | ... and so on.

Instead of a pipe-symbol, a simcolon could be also a proper separator between the column-items.

It would be great if you could add Parameter to Activities (Activity Parameter for Input and Output of Values).

Would be great if there was an extension for visual studio

It would be nice if a usecase descriptions can split in multiple requirement-items. Each items needs a short text field.

It would be nice if a usecase descriptions can split in multiple step-items. Each items needs a short text field.

It would be nice if it is visible on a UseCase component that a descriptions exists or not. A small Icon in the UseCase-Ellipse would be perfect.

Update extension GraphQL for StarUML 3.0